In 1999, the Edna McConnell Clark Foundation (EMCF) began an experiment that would ultimately reinvent its grantmaking. Starting with three grantees, it tested an approach for improving the life prospects of disadvantaged young people by investing heavily in the capacity of nonprofits to "scale up" programs of proven effectiveness. For the past 10 years, conducting more than 150 confidential interviews with leaders of more than 40 grantees, we have provided the Foundation ongoing feedback about the effects -- intended and unintended -- of its grantmaking. For this paper, we returned to our archive of interviews and examined the Foundation's own performance data to consider two questions:Have the Foundation's grantees moved the needle -- wit...